Tobamoviruses are mechanically transmitted plant viruses that cause severe economic damage to vegetable and ornamental crops in Florida and worldwide. While certain tomato cultivars have genetic ...resistance to the most common tobamoviruses, no commercial tomato cultivars are resistant to tomato brown rugose fruit virus (ToBRFV), a recently described tobamovirus that also infects pepper and eggplant. It is currently unknown how ToBRFV may affect tomato production in Florida. This new 5-page publication of the UF/IFAS Plant Pathology Department describes symptoms of the virus, how it is different from other tobamoviruses, and how it is transmitted, as well as what to do if you think you have ToBRFV in your field. Written by Ozgur Batuman, Salih Yilmaz, Pamela Roberts, Eugene McAvoy, Samuel Hutton, Kishore Dey, and Scott Adkins.https://edis.ifas.ufl.edu/pp360
Background: Tomato brown rugose fruit virus (ToBRFV) has spread worldwide affecting tomato crop production in several countries. Although there are commercial ToBRFV-resistant tomato varieties; ...still, careful monitoring of its prevalence is necessary for establishing feasible epidemiological control programs. Since Sonora has a strategic geographic location for tomato cultivation and export, studies on the detection and prevention of ToBRFV outbreaks are pertinent as part of the actions to achieve the eradication of this virus. Objective: To determine the recent prevalence of ToBRFV in tomato-producing areas of the state of Sonora, Mexico in the period 2021-2022, using a combination of molecular and serological tools. Methodology: Samples of tomato leaves and fruits were collected from commercial greenhouses in different regions of Sonora from September 2021 to June 2022. Forty-four tomato leaves and 42 seed samples were analyzed for ToBRFV using reverse transcriptase-polymerase chain reaction and by direct detection of viral epitopes by immunochromatography. Results: 60% and 48% of the samples tested positive for ToBRFV by immunochromatography and RT-qPCR, respectively, showing an exact agreement regarding the samples’ origin. Implications: Future research may focus on genomic analysis of viral isolates that would provide clues of ToBRFV propagation speed and emergence of particular viral strains typical of the place of origin. Conclusion: The presence of ToBRFV in the state of Sonora, Mexico is limited to specific geographic sites, which suggests that local regulations and phytosanitary actions have worked to control the spread of the virus.
Tomato brown rugose fruit virus (ToBRFV) is an emerging pathogen that causes severe disease in tomato (Solanum lycopersicum L.) crops. The first ToBRFV outbreak in Italy occurred in 2018 in several ...Sicilian provinces, representing a serious threat for tomato production. In the present work, the spatiotemporal displacement of ToBRFV in Sicily was evaluated, analyzing a total of 590 lots of tomato seed, 982 lots of plantlets from nurseries and 100 commercial greenhouses. Furthermore, we investigated the ToBRFV spreading dynamic in a greenhouse under experimental conditions. Results showed several aspects related to ToBRFV dispersion in protected tomato crops. In detail, an important decrease of the ToBRFV-infected seed and plantlet lots was detected. Regarding the examined commercial greenhouses, ToBRFV still appears to be present in Sicily, although there has been a decrease during monitoring. In experimental conditions, it was demonstrated that the presence of few infected plants are sufficient to damage the entire crop in a short time, reaching almost 100% of infection.
Nucleotide-binding leucine-rich repeat (NLR) plant immune receptors mediate the recognition and activation of defense signaling pathways in response to intra- and extracellular pathogens. Several NLR ...such as Tm-2 and Tm-2
2
have been introgressed into commercial solanaceous varieties to confer protection against different tobamoviruses. Particularly, Tm-2
2
was used during recent decades to confer resistance against tobacco mosaic virus, tomato mottle mosaic virus and tomato mosaic virus, which recognizes the viral movement protein (MP). However, tomato brown rugose fruit virus(ToBRFV), a novel tobamovirus, can avoid the protection conferred by Tm-2
2
due to the presence of key substitutions in the MP. The aim of this work was to identify the key amino acid residues involved in the interaction between Tm-2
2
and ToBRFV MP through bioinformatic analyses, and to identify potential Tm-2
2
mutations that could generate greater binding affinity.
In silico
3D structure prediction, molecular docking, and computational affinity methods were performed. We predicted that R350, H384 and K385 Tm-2
2
residues are relevant for the interaction with MP, and two mutations (H384W and K385L) were identified as putative sites to increase the affinity of Tm-2
2
to the MP with the potential elicitation of resistance against ToBRFV.
Tomato brown rugose fruit virus (ToBRFV) causes severe fruit loss in tomato (Solanum lycopersicum) and pepper (Capsicum annuum) plants. It is an emerging Tobamovirus that is spreading globally. The ...major challenge is to develop a reliable method for the detection of the virus, and to better characterize the symptoms it causes. The aims of this study, therefore, were to characterize the symptom development on tomato and pepper plants, and to establish a reliable detection method for the virus. Following infection of the tomato and pepper plants with ToBRFV, the leaves turned chlorotic, mosaic or mottled, while the fruit became rugose, necrotic and marbled, and showed discoloration with yellow or brown spots. Transmission electron microscopy (TEM) revealed single rod-like virus particles characteristic of the Tobamoviruses. Classical reverse transcription PCR (RT-PCR) and quantitative PCR (qPCR) with specific primers and probes confirmed that the virus is ToBRFV. We found that the resistance genes from tomato, Tm-22, and pepper, L1, L2, L3 and L4, did not confer resistance to ToBRFV. Here, we present a PCR-based method as a diagnostic test for detecting ToBRFV in infected seeds. This method will help to prevent further spread of the virus in commercial seeds.
Tomato brown rugose fruit virus (ToBRFV), belonging to the genus
, is a highly virulent emerging virus, causing disease outbreaks and significant crop losses worldwide. The growing number of ToBRFV ...epidemic episodes prompted the investigation of the role of seeds in the dissemination of the virus as an important aspect in the overall disease management. Therefore, the objectives of this study were to determine the localization of ToBRFV within tomato seeds and to evaluate its seed transmission characteristics. Seeds extracted from naturally ToBRFV-infected tomato fruits were tested for the presence of the virus using serological, molecular, and biological assays. Three immunolocalization techniques were used to determine the localization and distribution of ToBRFV within the different tissues and parts of tomato seeds. To evaluate seed transmission of ToBRFV, two grow-out experiments were conducted to assess the rate of both vertical (seeds to progeny seedlings) and possible horizontal transmission (plant to plant) based on serological and molecular assays. Seeds extracted from ToBRFV-infected fruits had a 100% contamination rate. The localization of ToBRFV in tomato seeds is only external on the seed coat (testa). Seed transmission rate from seeds to their seedlings was very low (0.08%), while no transmission was recorded from plants to plants in a small-scale greenhouse experimental setup. In conclusion, ToBRFV is a seedborne virus located externally on tomato seed coat and transmitted mechanically from ToBRFV-contaminated tomato seeds to seedlings, which could initiate a disease foci and eventually drive further dissemination and spread of the disease in a new growing area.
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